In recent years, mobile terminals such as a mobile phone have become diverse and multifunctional. Along with this, the diffusion rate of mobile terminals has been increasing, and mobile terminals have become essential to daily life. For example, a mobile phone not only makes a call but also has the function of connecting to the Internet, the function of picking up images, the function of playing music and moving images, and the like. Some mobile phones further have a credit function.
Against the above-described background, security functions of mobile terminals are attracting attention. As described above, amid the development of multifunctionality, mobile terminals are closely related to daily life, and most of them have a user's personal information recorded therein. A dial lock or the like is generally used as a security measure for a mobile terminal.
As a conventional technique related to mobile terminal security, the invention disclosed in Patent Document 1 is publicly known. Patent Document 1 discloses an invention in which a touch sensor is provided in a mobile phone to start a dial lock release sequence when a person contacts the touch sensor and a technique for shortening waiting time for unlocking using the invention and improving convenience. Patent Document 1: Japanese Patent Laid Open Publication No. 2005-268983.